The present invention relates generally to the use and production of hydrophobic fluids comprising chemical compounds having a characteristic fluorescence. More particularly these compounds are preferably porphyrins.
In the petroleum industry there are many needs for readily identifiable hydrophobic fluids. These needs, for example, include a means for identifying crude oil or petroleum products in efforts to discourage theft.
In the process of drilling a borehole to subterranean petroleum reservoirs, a drilling mud is circulated through the drill string and borehole to carry away the cuttings, cool the drill bit and perform a number of other important functions. This drilling mud, usually an aqueous suspension with numerous components, is essential for efficient drilling. In many cases the drilling mud being circulated requires special additives which may act as lubricants and as corrosion inhibitors, as well as having other functions. These additives are usually termed drilling mud conditioners.
Since the precise volume of circulating drilling mud is often unknown, events such as loss of circulation because of penetration into porous subterranean formations or the intrusion of subterranean water or brine may cause the circulating drilling mud to have a changed content. This changed content, particularly when an optimal level of drilling mud conditioner is advisable to maintain drilling efficiency, may result in unacceptably lowered levels of drilling mud conditioner. The present invention comprises a unique method for monitoring levels of drilling mud conditioner in circulating drilling mud.